Most modern automotive fuel systems utilize fuel injectors to deliver fuel to the engine cylinders for combustion. The fuel injectors are mounted on a fuel rail to which fuel is supplied by a pump. The pressure at which the fuel is supplied to the fuel rail must be controlled to ensure the proper operation of the fuel injectors. Pressure is controlled using pressure regulators that control the pressure of the fuel in the system at all engine r.p.m. levels.
Fuel flow rate through known pressure regulators tends to be low at high engine speed, as large quantities of fuel are consumed in the combustion process. At low engine speeds, less fuel is consumed in combustion and flow rates through the pressure regulators are high. These high fuel flow rates can produce unacceptably high noise levels.
A known pressure regulator includes a divider having a seat, a diaphragm and a retainer. The divider separates a housing into a first chamber and a second chamber. The seat defines a passage extending along a longitudinal axis of the housing between the first and second chambers. The seat includes a first portion proximate the first chamber having a first cross-sectional area and a second portion proximate the second chamber and having a second cross-sectional area. The first cross-sectional area is greater than the second cross-sectional area. The diaphragm extends between the housing and the seat. The retainer includes a plurality of apertures having a flow axis oriented along the longitudinal axis. The apertures diffuse flow and reduce operational noise of the regulator.
It is believed that there is a need for a pressure regulator that reduces flow-related noise at high fuel flow rates more than the known pressure regulator, while still being inexpensive to manufacture.